Recent studies in this laboratory have demonstrated that long-term survivors with Hodgkin's disease have significant abnormalities of immune function unassociated with the presence of active disease. Assays of non- specific immunity are abnormal in patients with Hodgkin's disease cured by MOPP chemotherapy. These abnormalities cannot be attributed to the chemotherapy since they are not present in patients with diffuse histiocytic lymphoma cured by similar chemotherapy regimens. T lymphocytes in both untreated and cured patients with Hodgkin's disease have increased sensitivity to suppression by normal immune regulatory cells. This has been shown for both a macrophage suppressor cell and T cell suppressor induced by concanavalin A. Both suppressor systems operate independently of prostaglandins. Studies have demonstrated the presence of suppressor B cells that regulate the proliferative responses of human T cells. Patients with Hodgkin's disease have